van backfires when accelerates on 2004 Mercury Monterey

my engines wont accelerate at normal temperatures,I have had the engine check and they said that piston#2 was misfirind.I have change the spak plugs and wires and st first does ok but after a while it begins hestating when accelerating,could u give me some possible solutions?

4 answers
With the check engine light on if the misfire is severe the check engine light will flash indicating catalytic converter damage is or will occur. It is best to attend to the misfire as soon as possible before it does secondary damage. The misfire could be due to a bad fuel injector, failed ignition coil, a vacuum leak, compression problem in that cylinder, a burned valve ect...
The engine has probably gone into "limp mode" to protect itself.
try the catalatic converter or clean the egr valve or idle control motor or ignition control module
had dealer look at this problem several times before they diagnosed a faulty spark plug wire back up under the dash
this mite be a injector that's gone bad, it when to me